Spunlaced loop material for a refastenable fastening device and methods of making same

ABSTRACT

A loop component for use in a hook and loop fastening system, and methods of making same are provided, wherein a spunlaced fabric having a plurality of loop structures is formed by entangling a plurality of non-interbonded fibers in a fibrous web of material. The loop structures are configured to engage hooks from a hook component having a hook density between about 30 and 400 hooks per square centimeter, and have a peel strength of between about 50 grams and 2000 grams. The spunlaced fabric may include a backing layer.

RELATED APPLICATION

This application claims the benefit of U.S. Provisional Application No.60/388,397, filed Jun. 12, 2002, the disclosure of which is incorporatedherein by reference in its entirety as if set forth fully herein.

FIELD OF THE INVENTION

The present invention relates generally to fastening systems and, inparticular, to loop material for hook and loop fastening systems.

BACKGROUND OF THE INVENTION

Hook and loop fastening systems are becoming prevalent in many durableand nondurable applications and are replacing other fastening devicessuch as tape, buckles, zippers and snaps. In general, hook and loopfastening systems include a male hook member, having a plurality ofupstanding hook engaging elements, and a female loop member having aplurality of loops in which the hook members become ensnarled to effectfastening engagement of the two components.

Unfortunately, many of the hook and loop fastening systems availabletoday can be difficult to manufacture or can have other drawbacks whichmay limit their utility. For example, woven and knit fabrics may requirecomplex equipment and multiple processes in order to construct a loopmaterial. Conventional nonwoven loop systems require inter-fiber bondingto reduce fiber spreading and accommodate hooks from a hook component.(e.g., see U.S. Pat. No. 5,326,612 to Goulait). Moreover, conventionalloop member material may not be soft enough for personal hygieneapplications, such as disposable diapers, surgical gowns, sanitarynapkins, etc.

SUMMARY OF THE INVENTION

Applicants have discovered that spunlaced fabric having non-interbondedfibers (i.e., fibers not bonded to other fibers) can be produced thatwill engage hooks of hook and loop fastening systems with acceptablepeel strength, as described in ASTM D-5170-98. A spunlaced fabric is afabric which has been formed by impinging a web (which can includepreformed fabrics, spunmelt webs, air laid webs and carded webs) withjets of high pressure water. Spunlaced fabrics have conventionally notbeen expected to offer any utility in the design of a loop material fora hook and loop fastening system. This is because the consolidation offibers via water jets has been considered unsuitable for forming loopsfor use in hook and loop fastening systems. However, Applicants haveunexpectedly discovered that a loop structure conducive to penetrationand engagement by hook members can be created from spunlaced fabrics.

According to embodiments of the present invention, a method of forming aloop component for use in a hook and loop fastening system includesforming a spunlaced fabric having loop structures with no inter-fiberbonds, and bonding the spunlaced fabric to a backing layer to produce aloop component. Loop components according to embodiments of the presentinvention can have loop structures configured to engage hooks from ahook component having a hook density between about 30 and 400 hooks persquare centimeter. Loop structures according to embodiments of thepresent invention can have a peel strength of between about 50 grams and2000 grams, and can have a shear strength of between about 1,000 and15,000 grams.

Embodiments of the present invention can provide aesthetically pleasinghook and loop fastening systems. Spunlaced loop member materialsaccording to embodiments of the present invention are superior toconventional loop member materials because of the visual consistency andsoft hand obtained. Moreover, loop members according to embodiments ofthe present invention have utility in a broad range of applications,particularly personal hygiene applications, such as disposable diapers,surgical gowns, sanitary napkins, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which form a part of the specification,illustrate embodiments of the present invention. The drawings anddescription together serve to fully explain the invention.

FIG. 1 is a flow diagram that illustrates methods of forming a loopcomponent for use in a hook and loop fastening system, according toembodiments of the present invention.

FIG. 2 is a flow diagram that illustrates operations for forming aspunlaced fabric having loop structures with no inter-fiber bonds,according to embodiments of the present invention.

FIGS. 3A-3V illustrate examples of bonding patterns that may be utilizedaccording to embodiments of the present invention.

FIG. 3W illustrates an exemplary print pattern that may be utilizedaccording to embodiments of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention now is described more fully hereinafter withreference to the accompanying drawings, in which preferred embodimentsof the invention are shown. This invention may, however, be embodied inmany different forms and should not be construed as limited to theembodiments set forth herein; rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

Referring now to FIG. 1, a method of forming a loop component for use ina hook and loop fastening system, according to embodiments of thepresent invention, includes forming a spunlaced fabric having aplurality of loop structures from a plurality of non-interbonded fibers(i.e., fibers not bonded to other fibers) in a fibrous web of material(Block 100), optionally embossing the spunlaced fabric with a decorativepattern or other decorative indicia (Block 200), and optionally bondingthe spunlaced fabric to a backing layer (Block 300).

A loop component according to embodiments of the present invention canhave loop structures configured to engage hooks from a hook componenthaving a hook density between about 30 and 400 hooks per squarecentimeter. The loop structures can have a peel strength of betweenabout 50 grams and 2000 grams (preferably 300-700 grams) using ASTMD5170-98, and can have peak shears of between about 1,000 and 15,000grams (preferably 1,800-9,000 grams) using ASTM D5169-91.

FIG. 2 illustrates operations for forming a spunlaced fabric having loopstructures with no inter-fiber bonds. Non-interbonded fibers in afibrous web of material are entangled to form a plurality of loopstructures by directing one or more jets of high-pressure water at thefibrous web of material (Block 110). The fibrous web may containrandomly oriented fibers or substantially aligned fibers. Exemplaryfibers include, but are not limited to, polypropylene, polyethylene,polyethylene terephthalate, polyester, acetate, nylon, viscose andacrylic, and blends thereof. Bicomponent fibers of such polymers mayalso be used. Exemplary fibrous webs include preformed fabrics, spunmeltwebs, air laid webs, carded webs, etc. The spunlaced fabric may behomogenous according to embodiments of the present invention.

Fibers within spunlaced fabrics, according to embodiments of the presentinvention, preferably have a denier of between about 0.5 and 19, and adensity of between about 0.1 and 1.2 grams per cubic centimeter.However, embodiments of the present invention are not limited to fibershaving this denier range or this density range. A spunlaced fabricaccording to embodiments of the present invention preferably has athickness of between about 10 and 95 mils. However, embodiments of thepresent invention are not limited to spunlaced fabrics having thisthickness range.

Well distributed and entangled fibers impart strength, consistency(visual coverage, uniform thickness and basis weight uniformity),smoothness and softness to spunlaced fabrics. The degree of fiberentanglement provided by water jet impingement can control the degree towhich the fabric fuzzes after repeated peels from a hook member.

According to embodiments of the present invention, a batt of fibrousmaterial may be formed above and below a spunbonded fabric or net.Fibers from the three layers may then be entangled via water jets(hydroentangling) to produce a spunlaced fabric.

The wet fibrous web of material may then be dried, for example using avacuum box and a dryer (Block 120). If a finish and/or color is to beadded to the spunlace fabric, a padder may be utilized, as is known tothose skilled in the art. Another dryer immediately following the padderto dry the fibrous web may also be utilized. Additionally, the web canbe apertured during the process.

The optional step of embossing a spunlaced fabric with a decorativepattern or other decorative indicia (Block 200) may provide additionaldimensional stability to the spunlaced fabric. FIG. 3W illustrates anexemplary decorative pattern that may be embossed and/or printed.Various decorative patterns may be utilized, however, withoutlimitation. Embossing may be performed in various ways including, butnot limited to, via thermal energy, ultrasonic energy, and/or heat andpressure. Preferably, the elements of the design have a pattern that hasdimensions between about 0.02 mm to 4.0 mm, and the repeat unit is about0.2 cm to 12.0 cm.

An optional backing layer may provide additional dimensional stability,and may increase the durability of the structure to hook release forcesand repeat engagements. A backing layer can also provide aesthetics byhaving various types of decorative indicia and/or colors. A backinglayer may also help reduce “fuzzing” of a spunlaced fabric afterrepeated “peels” from a hook member, and may help reduce fiber“pull-out” from the spunlaced fabric.

Bonding the spunlaced fabric to a backing layer to produce a loopcomponent (Block 300) may include bonding the spunlaced fabric tovarious types of materials. A composite backing layer and spunlacedfabric according to embodiments of the present invention may have a MD(machine direction) grab tensile strength of between about 10 pounds and40 pounds. Moreover, a composite backing layer and spunlaced fabricaccording to embodiments of the present invention may have a Frazier airpermeability of less than about 25 cubic feet per minute.

Bonding may be performed in one or more patterns. Bonding may be doneusing thermal or ultrasonic processes, autogenously, or may be attachedusing an adhesive, or using combinations of such techniques. The term“autogenously” means that the spunlaced fabric is secured to a backinglayer without the aid of a third material. For example, spunlaced fabriccan be fused or melted into a backing layer, and can be done so in apattern. The bond area may be between about 2.5% and 25% of the surfacearea of the backing layer. FIGS. 3A-3V illustrate various bond patternsthat may be utilized in accordance with embodiments of the presentinvention. However, it is understood that other bond patterns may alsobe utilized.

A backing layer may be a film, nonwoven fabric, lightweight wovenfabric, or knit scrim. If the backing layer is a film it may be producedfrom a polymer such as polypropylene, polyester, polyolefin, polyvinylalcohol, block copolymer, elastomeric polymer, copolyester, copolyetherester, urethane, styrene block copolymer, elastic foam, polyvinylchloride, copolyether amide such as Pebax®, or combinations thereof. Themost preferred polymer is a low-density polyethylene. Optionally, thefilm can be impervious to water. Film thickness may range from about0.00025 inches to about 0.010 inches, with the most preferred rangebeing from about 0.0006 inches to about 0.002 inches. The density of abacking layer film may be between about 0.65 grams per cubic centimeterand about 1.4 grams per cubic centimeter. Corona treatment of a backinglayer film is optional for embodiments of the present invention.

For fabric backing layers, all of the nonwoven technologies such asspunbonded, thermal bonded, resin bonded, needle punched, stitch bonded,flash spun, spunlaced, wet-laid, thru-air bonded, and others known tothose skilled in the art, would be appropriate. Paper, woven fabric, andknitted fabric could also be used.

Optionally, a fabric backing layer may be printed with a pattern,characters, and or other decorative indicia. A printed pattern and/orindicia may be used in addition to a pattern used in bonding.

Backing layers according to embodiments of the present inventionpreferably have a thickness of between about 0.4 and 40 mils, and adensity of between about 0.65 and 1.4 grams per cubic centimeter.However, embodiments of the present invention are not limited to backinglayers having this thickness range or this density range.

Hook and loop fastening systems according to embodiments of the presentinvention can be used as material for disposable diapers and othergarments, and can be attached to the waist portion of disposable diapersand other garments utilizing techniques known to those skilled in theart. For example, embodiments of the present invention can be used asthe waist band of a disposable diaper or other garment.

According to embodiments of the present invention, a hook and loopfastening system is provided that utilizes a female loop component asdescribed above in conjunction with a male hook component of virtuallyany type. Preferably, a loop component has loop structures configured toengage hooks from a hook component having a hook density between about30 and 400 hooks per square centimeter. Preferably, the loop structureshave a peel strength of between about 50 grams and 2000 grams using ASTMD5170-98, and have peak shears of between about 1,000 and 15,000 gramsusing ASTM D5169-91. Exemplary hook components are available, forexample, from Bender. Hook components may be formed from fibers of awide range of materials. Suitable materials include, but are not limitedto nylon, polyester, polypropylene, or any combination of these or othermaterials.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although a few exemplary embodiments ofthis invention have been described, those skilled in the art willreadily appreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. The invention is defined by the following claims, withequivalents of the claims to be included therein.

1. A loop component for use in a hook and loop fastening system,comprising a spunlaced fabric having a plurality of loop structuresformed only by entangling a plurality of non-interbonded fibers in afibrous web of material without a backing layer.
 2. The loop componentof claim 1, wherein the loop structures of the spunlaced fabric areconfigured to engage hooks from a hook component having a hook densitybetween about 30 and 400 hooks per square centimeter.
 3. The loopcomponent of claim 1, wherein the loop structures of the spunlacedfabric are configured to engage hooks from a hook component havingindividual hook lengths of 0.8 cm or less.
 4. The loop component ofclaim 1, wherein the loop structures of the spunlaced fabric have anaverage peel strength of between about 50 grams and 550 grams whentested using ASTM D5170-98 test method.
 5. The loop component of claim1, wherein the loop structures of the spunlaced fabric have an averagemaximum load peel strength of between about 100 grams and 2,000 gramswhen tested using ASTM D5170-98 test method.
 6. The loop component ofclaim 1, wherein the loop structures of the spunlaced fabric have anaverage peak shear strength of between about 1,000 and 15,000 grams whentested using ASTM D5169-91 test method.
 7. The loop component of claim1, wherein the loop structures of the spunlaced fabric maintain amaximum average peel strength after 20 test cycles between about 50 and550 grams when tested using ASTM D5170-98 test method.
 8. The loopcomponent of claim 1, wherein the fibers of the spunlaced fabric have adenier of between about 0.5 and
 19. 9. The loop component of claim 1,wherein the fibers of the spunlaced fabric have a density of betweenabout 0.1 and 1.2 grams per cubic centimeter.
 10. The loop component ofclaim 1, wherein the spunlaced fabric has a thickness of between about10 and 95 mils.
 11. The loop component of claim 1, wherein thenon-interbonded fibers of the fibrous web comprise fibers selected fromthe group consisting of polypropylene, polyethylene, polyethyleneterephthalate, polyester, acetate, nylon, viscose and acrylic, or blendsor bicomponents thereof.
 12. The loop component of claim 1, wherein thespunlaced fabric comprises homogenous spunlaced fabric.
 13. The loopcomponent of claim 1, wherein the spunlaced fabric comprises randomlyoriented fibers.
 14. The loop component of claim 1, wherein thespunlaced fabric comprises substantially aligned fibers.
 15. The loopcomponent of claim 1, wherein the spunlaced fabric comprises aperturedspunlaced fabric.
 16. The loop component of claim 1, wherein thespunlaced fabric comprises two or more layers of fibrous material. 17.The loop component of claim 1, wherein the spunlaced fabric is formedfrom a fibrous web via air laying.
 18. The loop component of claim 1,wherein the spunlaced fabric is formed from a fibrous web via carding.19. The loop component of claim 1, wherein the spunlaced fabric isembossed with a decorative pattern.
 20. The loop component of claim 19,wherein the decorative pattern comprises elements having dimensionsbetween about 0.02 mm and 4 mm. 21-52. (canceled)
 53. A hook and loopfastening system, comprising: a hook component having a hook densitybetween about 30 and 400 hooks per square centimeter; and a loopcomponent, comprising a spunlaced fabric having a plurality of loopstructures formed only by entangling a plurality of non-interbondedfibers in a fibrous web of material without a backing layer, wherein theloop structures of the spunlaced fabric are configured to engage hooksfrom the hook component.
 54. The hook and loop fastening system of claim53, wherein the loop structures of the spunlaced fabric are configuredto engage hooks having individual hook lengths of 0.8 cm or less. 55.The hook and loop fastening system of claim 53, wherein the loopstructures of the spunlaced fabric have an average peel strength ofbetween about 50 grams and 550 grams when tested using ASTM D5170-98test method.